Fuel cells have received attention in recent years as batteries with high efficiency and excellent environmental properties. Fuel cells generally generate electrical energy as a result of a chemical reaction between hydrogen, which is fuel gas, and oxygen in the air, which is oxidation gas. Types of fuel cells include phosphoric acid fuel cells, molten carbonate fuel cells, solid state electrolyte fuel cells, alkaline fuel cells, solid state polymer fuel cells, and so on. Among these types of fuel cells, solid state polymer fuel cells having an advantage that the fuel cell can start at room temperature with high-speed starting and so on are attracting particular attention.
A single cell used in a solid state polymer fuel cell includes an electrolyte membrane, a catalyst layer, a gas diffusion layer, and a separator. An assembly in which an electrolyte membrane, a catalyst layer, and a gas diffusion layer are integrated is generally referred to as a membrane electrode assembly (MEA).
Surface treatment processing such as plasma treatment, primer coating, adhesive coating, and so on is generally applied to a surface of a fuel cell separator forming the single cell. JP 2003-22817 A, for example, describes a method of applying a sealing material to a separator which is placed on a sealing material coating station while sucking the separator with negative pressure which is generated when compressed air is generated.
Here, a fuel cell separator, e.g. a metal separator formed of titanium and so on, may have local warpage or waviness. FIG. 5 illustrates a fuel cell separator 42 which has been warped. As shown in FIG. 5, the warpage of the fuel cell separator 42 generally increases at end portions of the fuel cell separator 42. The amount of warpage of the fuel cell separator 42 having a thickness of 0.1 mm, for example, is about 5 mm.
When an adhesive or the like is applied to the surface of the fuel cell separator 42, an adhesive application gun, for example, may be used. FIG. 6 illustrates a method for applying an adhesive 44 onto a surface of the fuel cell separator 42 using an adhesive application gun or the like. Here, in order to keep the adhesive 44 applied on the surface of the fuel cell separator 42 at a substantially constant amount, a clearance between the surface of the fuel cell separator 42 and a nozzle 46 of the adhesion application gun is maintained substantially constant within the range between 0.9 mm or more and 1.2 mm or less, for example.
However, when the fuel cell separator 42 is warped, for example, as shown in FIG. 5, the amount of the adhesive which is applied varies between the substantially center portion and the end portions of the fuel cell separator 42. This may result in a case where the adhesive 44 cannot be applied in a predetermined amount. Further, when an adhesive is applied to the fuel separator by using the sealing material application method described in JP 2003-22817 A as described above, as a negative pressure is generated by ejection of compressed air, it may be difficult to correct a fuel cell separator which is warped.
It is therefore an advantage of the present invention to provide a separator suction device for a fuel cell, capable of correcting warpage or the like of a fuel cell separator in a simple manner, and holding the fuel cell separator.